Method of making gear heating coils



Feb. 3, 194a. H. E. SOMESI 2,435,242

METHOD OF MAKING GEAR HEATING COILS Filed Jan. 11, 1945 3 Sheets-Sheet 1,

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/ 2 I INVEN TOR.

Howardfi'. 'omes Feb. 3, 1948'. H; E. SOMES 2,435,242

' METHOD OF: MAKING GEAR HEATING COILS Filed.Jan. 11, 1945 s Sheets-Sheet 2 INVENTOR.

.l/owdrd/E'. James By v,

firm/may Feb.- 3, 1948. H. E. SOMES METHOD OF MAKING GEAR HEATING COILS Filed Jan. 11, 1945 llll llillli- 3 Sheets-Sheet 3.;

FTTOENEY Patented Feb. 3, 1948 METHOD OF MAKING GEAR HEATING COILS Howard E. Some s, Detroit, Mich, assignor, by mesne assignments, to The Budd Company, Philadelphia, Pa., a corporation oi Pennsylvania Application January 11, 1945, Serial No. 572,318

6 Claims. 1

This invention relates to the method of making I an inducing coil, particularly a, coil for use in the heat treating of gears and other toothed structures.

Heretofore, it has been one practice in the induction heat treatment of gears andtoothed members to utilize a multiturn coil of uniform cross-section arranged in concentric relation with the gear or toothed member. In such practice, it is not possible to heat the teeth to a uniform depth.

One of the objects of the present invention is to provide a multi-turn inducing coil oi improved construction wherein the coil is provided with toothed portions complemental to a toothed surfaceto be heat treated.

Another object is to provide a new and eillcient methodof forming an inducing coil with toothed portions.

A further object is to provide a method of pro-.

ducing a multi-tum coil from an annular blank of metal.

with the above andother objects in view which will be apparent from the following description to those skilled in the art to which the invention appertains, the present invention consists in certain features of construction andproce'dure to be hereinafter described with reference to the accompanying drawings, and then claimed.

In the drawings which illustrate a suitable embodiment of the invention;

Figure 1 i a, side elevation of the blank, partially in section, from which the coil is formed:

Figure 2 is a view of the blank as it appears after the first forming operation;

Figure 3 is a similar view of the blank after it has been cut to spiral form;

Figure 4 is a view showing the spiral formation and the coil cooling passage closed in;

Figure 5 is a sectional view showing the spiral formation of Figure 4 positioned within the coil holder;

Figure 6 is a view similar to Figure 5 but showins the teeth formed in the coil; and

Figure 7 is a transverse section taken tially on line L-I of Figure 6.

Referring to the accompanying drawings in which like numerals refer to like parts throughout the several views, and, first, to Figures 6 and '7 in particular, the inducing coil I is in the form substanof a spiral winding having its ends terminating at one side substantially in alignment with each other. The coil is formed with a continuous external channel 2, the sides of which are formed with shoulders 3 to receive a spiral closure strip 0 which closes in the channel to provide apassage for the circulation of a cooling medium through the coil. At the ends, the channel 2 is provided with inlet and outlet connectors 5 and 8, respectively, brazed or otherwise secured thereto, which connections open into the channel or cooling medium passage. The closure strip ends are brazed to the connectors 5 and 6.

The turns of the coil are electrically insulated from each other by a strip 1 of suitable insulation material.

The particular coil shown for illustration is adapted for inducing heating currents in an external spiral gear (not shown) and to this end is provided with spiral teeth 8 complementary to the teeth oi the gear to be heated thereby.

The support for the coil I includes an annular sleeve or casing O which surrounds an annulus ll of taper ground laminations of suitable magnetic material, the annulus having an internal recess which in effect provides radially inwardly extendingpole portions II. The coil is disposed within this recess and is electrically insulated from the bottom of the recess by an insulating strip I2 and from the pole portions II by built-up insulation strips I3. The annulus of laminations is formed with apertures II through which the connectors l and 6 extend, the connectors being electrically insulated from the laminations by suitable insulation II. The casing 9 is provided with openings II and H which we aligned with the connectors 6 and 6 for the reception of conduits (not shown), which in use are connected with the connectors i and B to conduct a cooling medium thereto and therefrom.

Suitable annular end plates I8 and I9 are secured by screws 20 and 2|, respectively, to the end faces of the casing whereby to hold the annulus Ill of laminations and thereby the coil I firmly in position within the casing. n

Since the teeth 8 are at least substantially complemental to the teeth of the gear to be heated and the teeth of one coil tum form continuations'of those in the next adjacent turn or turns, it is obvious that the teeth in the adjacent turns should be formed in such manner as p to be properly aligned with each other.

In the forming of the coil, a tubular blank (Figure 1) of suitable electrically conductive material is first selected and machined to proper thickness. This blank is first machined externally to provide the spiral channel 2 and the edge shoulders 3 (Figure 2).

In the next operation, the blank is machined to proper dimensions and spirally severed around 3 the ridge between adjacent channels (Figure 3) to form .the turns of the coil I.

Following thi operation, the connectors I and I are brazed or otherwise suitably secured to the cell at the channel ends and then the spiral strip 4 is brazed or otherwise suitably secured in place in seated engagement with the shoulders I to close the channel 2 and thereby form the coolin medium passage (Figure 4). Also at this time the insulation strip 1 is disposed between the coil turns. a

The unit of Fi ure 4 and the laminated element iii are then assembled together and disposed within the annular casing 9 (Figure 5), after which the annular end plates l8 and II are secured by the screws 20 and 2|, respectively, to the casing 8 to securely clamp the coil assembly inposition.

With the coil i thus securely clamped in position, the spiral teeth 8 are then cut by means of a suitable tooth forming operation in the inner face of the coil i.- Since the coil is securely clamped and the coil turns are rigidly held against relative movement, the teeth formed in each turn will be in accurate and proper alignment with each adjacent turn.

It will be seen from the foregoing that a method has been provided which is particularly advantageous in forming a multi-turn coll having teeth or projecting portions at one surface thereof.

While the coil itself is shown as provided with spiral teeth, the same may be provided with axial teeth for heating spur gears. The coil is of particularly advantageous construction inasmuch as through its complementary or substantial y complementary contour, that is, complementary with respect to a toothed surface to be heated, it provides a means whereby a gear or the like may be inductively heated to a uniform depth not only throughout the tooth faces but also the tips of the teeth and the surfaces between the teeth as we 1.

The invention is equally as applicable to coils for heating internally toothed structures.

It is to be understood that various changes may be made in the construction and procedure described without departing from the spirit and substance of the invention, the scope of which is defined by the appended claims.

What is claimed is:

1. The method of forming a multi-turn inducing coil which consists in spirally severing an annular blank of electrically conductive material into multi-turn formation to form a cylindrical helix having inner and outer circumferential surfaces, rigidly holding the coil turns against relative movement, and then machining teeth in one circumferential face of the coil across a plurality of turns whereby the tooth elements of adjacent turns are in accurate alignment.

2. The method of forming a multi-turn inducing coil which consists in spirally severing an annular blank of electrically conductive material into multi-turn formation to form 9, cy lindrical helix having inner and outer circumferential surfaces, disposing insulating material between the coil turns, rigidly mounting the coil .6 Number on a supporting member to hold the turns accurately in position, and'then machining teeth in one circumferential face of the coil so mounted across a plurality of turns whereby the tooth elements of adjacent turns are in accurate alignment.

3. The method of forming a multi-turn inducing coil which consists in machining a spiral channel in one circumferential surface of an an- 1 nular blank of electrically conductive material and spirally severing the blank between adjacent channel turns into multi-turn formation to form a cylindrical helix having inner and outer circumferential surfaces, and while securely holding the coil against relative movement between its turns forming teeth in the other circumferential surface thereof across a plurality of turns whereby the tooth elements of adjacent turns are in accurate alignment.

4. The method of forming a multi-turn inducing coil which consists in machining a spiral channel in one circumferential surface of an annular blank of electrically conductive material, closing in the open side of said channel, cutting the blank through its wall along a path between adjacent channel turns to form the blank to cylindrical helical coil formation, inserting insulating material between adjacent coil turns, securely mounting the coil on a support with the surface opposite the channeled surface exposed, and then forming spaced teeth in said opposite surface across a plurality of turns whereby the tooth elements of adjacent turns are in accurate alignment.

5. The method of forming an annular hollow multi-turn inducing coil which consists in machining a spiral channel in one circumferential surface of an annular blank of electrically conductive material, severing the wall of the blank between adjacent channel turns to provide amulti-turn coil formation, and then closing in the open side of the channel to provide a closed passage.

6. The method of providing a multi-turn inducing coil having spaced teeth in one circumferential surface thereof, which consists in forming an element of electrically conductive material into a multiturncylindrical helix of annular shape, disposing insulation material between the coil turns, mounting the coil 50 insulated on a support having contact with one circumferential surface thereof and with the coil turns held against a relative axial movement, and then forming spaced teeth in the opposite 'circumferential surface of the coil across the several turns, whereby ".the tooth elements of adjacent turns are in accurate alignment.

' HOWARD E. SOMES.

asrsnsncss crran nm'rnn s'rwrss PATENTS Name Date 1,703,707 Browne Feb. 26, 1929 2,241,431' Somes May 1.3, 1941 

